EU/3/11/857

Orphan designation

On 15 April 2011, orphan designation (EU/3/11/857) was granted by the European Commission to Voisin Consulting S.A.R.L., France, for synthetic double-stranded siRNA oligonucleotide directed against transthyretin mRNA for the treatment of familial amyloid polyneuropathy.

Familial amyloid polyneuropathy (FAP) is a hereditary (‘familial’) disease caused by a defective gene for transthyretin, a protein that transports various substances in the blood. Transthyretin is primarily produced in the liver.

Patients with FAP have an abnormal transthyretin protein that breaks up easily and accumulates in various tissues in the body, especially tissues of the nervous system, in the form of insoluble, waxy ‘amyloid’ structures. The condition mainly affects the nervous system causing symptoms such as muscle weakness in the limbs and, at later stages, inability to walk, problems affecting the stomach and the gut (leading to malnutrition), and bladder dysfunction.

FAP is a long-term debilitating disease due to the progressive worsening of nervous system symptoms. It is also life threatening because the amyloid deposits may accumulate in the heart and cause fatal heart conditions.

At the time of designation, FAP affected less than 0.1 in 10,000 people in the European Union (EU)*. This is equivalent to a total of fewer than 5,000 people, and is below the ceiling for orphan designation, which is 5 people in 10,000. This is based on the information provided by the sponsor and the knowledge of the Committee for Orphan Medicinal Products (COMP).

*Disclaimer: For the purpose of the designation, the number of patients affected by the condition is estimated and assessed on the basis of data from the European Union (EU 27), Norway, Iceland and Liechtenstein. This represents a population of 506,300,000 (Eurostat 2011).

The medicine is made of a small strand of synthetic genetic material, called ‘small interfering RNA’ (siRNA), that interferes with the expression of certain genes. It has been designed to target the defective gene in patients with FAP, where it is expected to block the production of the abnormal transthyretin protein in the liver, thereby reducing the accumulation of amyloid deposits in the tissues and slowing down the progression of the disease.

the existence of alternative methods of diagnosis, prevention or treatment;

either the rarity of the condition (affecting not more than 5 in 10,000 people in the EU) or insufficient returns on investment.

Designated orphan medicinal products are products that are still under investigation and are considered for orphan designation on the basis of potential activity. An orphan designation is not a marketing authorisation. As a consequence, demonstration of quality, safety and efficacy is necessary before a product can be granted a marketing authorisation.